Pick one thing at a time and keep bringing yourself back to it. If it's time to work on a homework assignment, do that for X period of time. Write things down, rank order them. Only write down 5 things at a time/per day as it's not likely that more will get done.

I don't know about "squeezing out" another child if you don't feel you can take care of yourself very well? Children are not things on a to-do list like homework or cleaning house.